Also think about the ability to adapt lenses with shorter registrations than Nikon or Canon EOS like Leica M, Zeiss ZM and Canon FD as well as Nikon and Canon. If you're a legacy lens fan like I am, the D5300 won't be able to do as much although Nikon has an extensive number of classic Nikkors that are nice to use.

The D5300 is not very usable with older Nikkors. It won't autofocus with AF-D lenses and won't meter with AI lenses. If you're not willing to stick with AF-S lenses, it's just not a good choice.

The A6000 will meter with AI lenses.

I would say the Nikon only has more lenses available if you need autofocus on all your lenses.

it needs glassless adapters but the Sony can AF Canon EF, Sony/MInolta , Contax G as well as native E/FE.

AF with some of those is slow but others is as fast as natively I think.....you have to add the cost of the adapters but in fact the Sony E mount has probably MORE lenses that can AF than any other.